1. Technical Field
The present invention generally relates to a semiconductor device, to a sense amplifier circuit, and a semiconductor device using the same.
2. Related Art
A semiconductor device is driven by for power and thus is configured to include a sense amplifier circuit for sensing a difference in the voltage level and for converting the difference into a digital level. A sense amplifier circuit may sense a difference between the voltage levels of input signals. An input signal having a relatively high voltage level according to a result of the sensing is amplified in a high level and outputted, and an input signal having a relatively low voltage level according to a result of the sensing is amplified in a low level and outputted. A sense amplifier circuit using another method amplifies an input signal, having a relatively low voltage level, into a signal of a low level so that the input signal having a relatively low voltage level is clearly distinguished from an input signal having a relatively high voltage level.
FIG. 1 is a diagram illustrating the construction of a known sense amplifier circuit. Referring to FIG. 1, the sense amplifier circuit 10 includes first to fifth transistors N1, N2, N3, N4, and N5, respectively. The left side of the sense amplifier circuit 10 corresponds to an input terminal, and the right side thereof corresponds to an output terminal. The first transistor N1 is turned on in response to a sense control signal EN when a signal is transmitted from the input terminal to the output terminal, thus supplying a ground voltage VSS. The degree of turn-on of the second and the third transistors N2 and N3 varies according to the levels of input signals IN and INB when a signal is transmitted from the input terminal to the output terminal. Accordingly, the first to third transistors N1, N2, and N3, respectively, may generate output signals OUT and OUTB by amplifying the input signals IN and INB. The fourth and the fifth transistors N4 and N5 are turned off when a signal is transmitted from the input terminal to the output terminal, but are turned on in response to a control signal WE when a signal is transmitted from the output terminal to the input terminal. When the fourth and the fifth transistors N4 and N5 are turned on, they couple the input terminal and the output terminal.
The operation of the sense amplifier circuit 10 when a signal is transmitted from the input terminal to the output terminal is as follows. When the input signal IN has a higher level than the input signal INB, the degree of turn-on of the second transistor N2 is greater than the degree of turn-on of the third transistor N3. Accordingly, the output terminal OUTB drops to a ground voltage (VSS) level faster than the output terminal OUT. When the output signal OUTB reaches the ground voltage (VSS) level, a difference in the voltage level of the input signals IN and INB is amplified and thus the amplified output signals OUT and OUTB may be outputted through the output terminal.
The sense amplifier circuit 10 starts a sense amplification operation when the sense control signal EN is enabled. The sense control signal EN turns on the first transistor N1 that supplies the ground voltage VSS, Accordingly, a point in time at which the sense control signal EN is enabled is closely related to a precise operation of the sense amplifier circuit 10. For example, if the input signals IN and INB are not supplied at normal points in time, the levels of the output signals OUT and OUTB may be reversed or points in time at which the output signals OUT and OUTB are generated may be delayed.
Furthermore, even when a mismatch occurs between the second and the third transistors N2 and N3, respectively, which substantially perform a sense operation, the output signals OUT and OUTB may not be normally generated.